Programmatic control of RFID tags

Abstract

Techniques that enable a device to advertise its mode of operation using an RFID tag attached to the device. Techniques are provided for programmatically controlling an RFID tag. An RFID tag attached to a device is programmatically enabled or disabled depending upon the mode(s) of operation of the device. The RFID tag is able to transmit a signal when enabled and not able to transmit a signal when disabled. Using such a controllable RFID tag, a device can efficiently indicate or advertise its mode of operation to an RFID reader or sensor.

What is claimed is: 
     
       1. A method of controlling a radio frequency identification (RFID) tag associated with a device, the device being capable of operating in at least a first mode and a second mode, the method comprising:
 upon a change in operating mode of the device from the first mode to the second mode, receiving, at a controller apparatus coupled to the RFID tag, a first indication that the device is operating in the second mode; 
 enabling, by the controller apparatus, based on the first indication, transmission of signals by the RFID tag, wherein the RFID tag is a passive RFID tag, and 
 wherein the enabling comprises unclamping two poles of an antenna of the RFID tag. 
 
     
     
       2. The method of  claim 1  further comprising:
 upon the device returning to operating in the first mode, receiving a second indication at the controller apparatus; and 
 disabling, by the controller apparatus, based on the second indication, transmission of signals by the RFID tag. 
 
     
     
       3. The method of  claim 2  wherein the disabling comprises clamping the two poles of the antenna of the RFID tag together. 
     
     
       4. The method of  claim 2  wherein the first indication corresponds to logic high and the second indication corresponds to logic low. 
     
     
       5. The method of  claim 1  further comprising:
 transmitting a signal from the RFID tag when the device is operating in the second mode. 
 
     
     
       6. The method of  claim 5  wherein the transmitting comprises:
 receiving, at the RFID tag, an interrogation signal from a reader; and 
 transmitting the signal from the RFID tag in response to the interrogation signal using energy harvested from the interrogation signal. 
 
     
     
       7. The method of  claim 2  wherein the first and the second indications are generated by a mode detection module coupled to the device. 
     
     
       8. The method of  claim 1  wherein the controller apparatus comprises a reed relay. 
     
     
       9. The method of  claim 2  wherein:
 the controller apparatus comprises a reed relay; and 
 the first indication causes the reed relay to be placed in an open state and the second indication causes the reed relay to be placed in a closed state. 
 
     
     
       10. A system comprising:
 a device configured to operate in a first mode and a second mode different from the first mode; 
 a passive radio frequency identification (RFID) tag coupled to the device; and 
 a controller apparatus coupled to the RFID tag; 
 wherein the controller apparatus is configured to:
 upon a change in operating mode of the device from the first mode to the second mode, receive a first indication that the device is operating in the second mode; and 
 enable, based on the first indication, transmission of signals by the RFID tag by unclamping two poles of an antenna of the RFID tag. 
 
 
     
     
       11. The system of  claim 10  wherein the controller apparatus is further configured to:
 receive a second indication when the device is operating in the first mode; and 
 disable, based on the second indication, transmission of signals by the RFID tag. 
 
     
     
       12. The system of  claim 11  wherein the controller apparatus is configured to disable transmission of signals by the RFID tag by clamping the two poles of the antenna of the RFID tag together. 
     
     
       13. The system of  claim 10  wherein the controller apparatus comprises a reed relay. 
     
     
       14. The system of  claim 11  wherein:
 the controller apparatus comprises a reed relay; and 
 the reed relay is placed in an open state upon receipt of the first indication and the reed relay is placed in a closed state upon receipt of the second indication. 
 
     
     
       15. The system of  claim 10  wherein the RFID tag is configured to:
 receive an interrogation signal from a reader; 
 harvest energy from the interrogation signal; and 
 transmit a signal in response to the interrogation signal using the energy harvested from the interrogation signal. 
 
     
     
       16. The system of  claim 11  wherein the first indication corresponds to logic high and the second indication corresponds to logic low. 
     
     
       17. The system of  claim 10  wherein the RFID tag is configured to:
 transmit a signal when the device is operating in the second mode. 
 
     
     
       18. The system of  claim 11  further comprising:
 a mode detection module coupled to the device and configured to generate the first and the second indications. 
 
     
     
       19. The method of  claim 1 , wherein the device is capable of performing a function in the second mode and not capable of performing the function in the first mode. 
     
     
       20. The method of  claim 1 , wherein the device is powered in the second mode and the device is not powered in the first mode. 
     
     
       21. The system of  claim 10 , wherein the device is capable of performing a function in the second mode and not capable of performing the function in the first mode. 
     
     
       22. The system of  claim 10 , wherein the device is powered in the second mode and the device is not powered in the first mode.